EP1507665B1 - Inkjet printing device - Google Patents

Abstract

The invention relates to an inkjet printing apparatus ( 1 ) with at least one printing head ( 2 ). Several tanks ( 3, 4 ) for inks and/or a cleaning medium are arranged in front of a connection opening ( 7 ) for the printing head ( 2 ), and the tanks ( 3, 4 ) are connected by feed lines ( 5 ) with the connection opening ( 7 ) for the printing head ( 2 ), whereby a stop element ( 6 ) is arranged between each tank ( 3, 4 ) and the connection opening ( 7 ).

Description

The invention relates to an ink jet printing device and a print head for ink jet printing devices, as described in the preamble of claims 1, 31.

Ink jet printing devices or ink jet printers have already become known in which a nozzle or a nozzle group of a print head for depositing or discharging inks is preceded by an ink tank or ink reservoir. The ink reservoir is connected via channels to the nozzle or the nozzle group on the one hand and via a feed line to the ink tank on the other hand. The disadvantage was that due to this type of ink supply only printing devices were produced with which only one type of inks can be processed. For processing different inks it required a complete conversion of the machine.

The need for ink jet printers with different ink systems, i. To be able to operate inks of different types is particularly given in the industrial sector, with which one and the same printing device imprints on different materials, such as paper, cardboard, plastic films or textiles, should be done. For this purpose, solutions have already been proposed that allow retrofitting of an inkjet printer for different ink systems.

In the US 6024441 A An ink jet printing device consisting of ink tanks, flexible feeding lines and printhead connecting units will be described. For the different colors of each different ink systems lead feeder lines from the ink tanks to each one belonging to an ink system connection unit. The printheads of the inkjet printing device are in turn connected to printhead connectors at the printhead connector units, thereby ensuring ink supply to the printheads. To convert the inkjet printing device to a new ink system, it is necessary that the printheads be removed from the inkjet printing device by detaching the printhead connectors from the printhead connector units. The pushbuttons are then replaced with the new set of printheads connected to the printhead connection units of the new color system. The change of the ink system in inkjet printing devices, as in US 6024441 A described is thus associated with a considerable manipulation effort to remove or install the printheads.

document US4908638 discloses a multi-color printer with multiple printheads.

The present invention has for its object to provide an ink jet printing device that allows a universal use, without long changeover times at the inkjet printer.

This object of the invention is achieved by the claim 1. It is advantageous in this embodiment that now with a set of printheads different ink systems or inks with different properties, viscosity, color, dye concentration, etc. can be processed. For retooling, the various tanks are to be connected to the printheads merely by appropriate adjustment of the shut-off devices, however, a change of the printheads or a complete retrofitting of the ink jet printing device or of the ink jet printer is not required and yet the advantages of each type of ink can be exploited via a single ink jet printing device ,

The development of the ink jet printing device according to claim 2 provides the advantage that with the reservoirs an intermediate or buffer memory for the storage of inks is available, and thus a safeguard against interruptions due to empty tanks is given.

The development of the ink jet printing device according to claim 3 offers the advantage that the ink can flow into the print head to the required extent and thus impairments in print quality can be avoided.

By the development of the ink jet printing device according to claim 4, wherein a reservoir is arranged in the print head, ink jet printing devices of a much more compact design can be produced in an advantageous manner.

Also advantageous is a development of the inkjet printing device according to claim 5, since it can be found with fewer components Auslangen. By forming the shut-off valves by a common multiway valve, the risk of malfunction is also reduced, since it is not possible that simultaneously from several tanks inks or the cleaning medium can flow into the print head.

The development of the inkjet printing device according to claim 6 offers the advantage that the supply of the ink or the cleaning agent in the print head is independent of the gravitational effect and thus the tanks in any areas of the inkjet printer can be arranged. The pump ensures the delivery of the ink or the cleaning agent in any case.

By the formation of the inkjet printing device according to claim 7 can be avoided in an advantageous manner that impurities enter the printhead and the nozzles are clogged.

Also advantageous is the development according to claims 8 and 9, as a pressure decoupling of the ink in the print head or in the corresponding reservoir from the pressure in the corresponding tank can be achieved.

Due to the developments of the ink jet printing device according to claim 10 to 14, the advantage is achieved that the inks can always be kept in the most favorable for their processing range of the operating temperature and the supply of the print head with ink can be automated and especially programmatically done.

The design of the ink-jet printing device according to claim 15 offers the advantage that it can be used to produce ink-jet printing devices with a very wide range of applications. Ink jet printers with such inkjet printing devices can be used in inkjet printers of various types and applications.

Also advantageous is the development according to claim 16, since the thus possible cleaning of the print heads, the conversion of the ink jet printing device can be significantly reduced to a new ink system and thus, in particular misprints can be avoided by the temporary and undesirable mixture of inks of different ink systems.

The development of the inkjet printing device with a level sensor according to claim 17 and 18 offers the advantage that it can be used to determine the level of the inks in the reservoirs. This can also be achieved that are always sufficient amounts of ink in the reservoirs and thus prevents the depletion of the ink reservoir in the reservoirs and it comes to an interruption of the printing process or, as a result, to misprints.

By the formation of the ink jet printing device according to claim 19 to 22, by the reservoir or the distribution chamber with ventilation openings or a pressure control valve, in particular a servo valve are formed, it is advantageously ensured that the ink from the reservoir can flow freely into the region of Aussprühvorrichtungen , This avoids that pressure fluctuations in the distribution chamber of the printhead occur and as a result different sized ink droplets are ejected from the printhead, whereby the print quality is affected.

The development of the ink jet printing device according to claim 23 offers the advantage that penetration of dust particles from the ambient air into the print head and subsequently clogging of the nozzles of the print head can be prevented.

Also advantageous is the development of the ink jet printing device according to claims 24 and 25, since thereby the ink supply disturbing pressure fluctuations in the feeder lines and the reservoirs can be reduced. In fact, pressure fluctuations occur in particular as a result of the acceleration forces acting on the ink which occur across the print medium during the movement of the print head in the transverse feed direction.

By the constitution of the ink-jet printing apparatus according to claim 26, there is obtained the advantage that in the case where an ink is not in use, it can be circulated and hence the deposition of components of the ink in the pipes can be prevented.

By the constitution of the ink-jet printing apparatus according to claim 27, the advantage is achieved that the arrangement of the ink tanks can be made more compact and, in particular, with a smaller number of tanks for the different colors of the inks of the different ink systems can be found Auslangen.

Finally, a refinement of the ink jet printing device according to claims 28 and 29 is also advantageous, since the control of the various operating states of the ink jet printing devices can be automated or program-controlled.

The further development of the ink-jet printing device according to claim 30 provides the advantage that the supply of the ink-jet printing device with ink or the required Cleaning medium for longer periods can be ensured and so uninterrupted operation of the ink jet printing device can be ensured.

The design of the inkjet printing device according to claim 31 provides the advantage that, with a set of printheads for the required number of colors, inks of different ink systems can be processed. To switch between the different ink systems, it is only necessary that the shut-off valves of the print head are closed or opened accordingly. It is also advantageous that, when switching to a new ink system, the remainders of the inks remaining in the reservoirs do not have to be removed and thus material losses can be reduced.

The formation of the print head according to claims 32 to 34, in that the reservoirs are formed with ventilation openings, advantageously ensures that the ink from the reservoirs can flow into the area of the ejection devices in the extent required for trouble-free operation.

The development of the print head according to claim 35 ensures in an advantageous manner that no dust particles or impurities from the air penetrate into the nozzles of the print head and these clogging can.

Also advantageous is the development of the print head according to claim 36, since it is thereby possible to keep the inks in the most favorable in their processing temperature range.

The design of the printhead according to claim 37 makes it possible in an advantageous manner to be able to bring such printheads for the processing of a variety of ink systems and in inkjet printers of various types used.

With the formation of the printhead of claim 38, it is possible to substantially reduce the time required to convert to the inks of a new ink system and, at the same time, to avoid the losses of inks by undesirably mixing the inks of different ink systems.

For a better understanding of the invention, this will be explained in more detail with reference to the following figures.

Fig. 1

eine Tintenstrahldruckeinrichtung mit einem Druckkopf;

Fig. 2

einen Druckkopf mit mehreren Reservoirs für Tinten bzw. ein Reinigungsmedium;

Fig. 3

ein Detail eines Tintenstrahldruckers mit drei Tintenstrahldruckeinrichtungen gemäß Fig. 2 in perspektivischer und vereinfachter Darstellung.

In a simplified schematic representation:

Fig. 1

an ink jet printing device having a print head;

Fig. 2

a print head having a plurality of reservoirs for inks or a cleaning medium;

Fig. 3

a detail of an ink jet printer with three ink jet printing devices according to Fig. 2 in perspective and simplified representation.

By way of introduction, it should be noted that in the differently described embodiments, the same parts are provided with the same reference numerals or the same component names, wherein the disclosures contained in the entire description can be mutatis mutandis to the same parts with the same reference numerals or component names. Also, the location information chosen in the description, such as top, bottom, side, etc. related to the immediately described and illustrated figure and are to be transferred to the new situation mutatis mutandis when a change in position. Furthermore, individual features or combinations of features from the different exemplary embodiments shown and described can also represent independent, inventive or inventive solutions.

The Fig. 1 shows an ink jet printing device 1 with a print head 2.

The inkjet printing device 1 consists of three tanks 3 for holding different inks and a tank 4 for receiving a cleaning medium, wherein the tanks 3, 4 are connected by feeder lines 5 with a shut-off device 6 and a connection opening 7. The connection opening 7 of the obturator 6 is connected to a feed opening 8 of the print head 2. The obturator 6 of the ink jet printing device 1 is formed in the concrete embodiment as a multi-way valve. Of course, it is also possible that each feeder line 5 has a separate valve and the outlet openings of these valves open into a common connection opening 7.

The connection opening 7 for the print head 2 are thus preceded by a plurality of tanks 3, 4 for inks and / or a cleaning medium, the tanks 3, 4 being connected by feeder lines 5 to the connection opening 7 and between each tank 3, 4 and the connection opening 7 Shut-off valve 6 is arranged.

Between the ink tanks 3 and the obturator 6 is in the course of the feeder line 5 each have a reservoir 9. These reservoirs 9 are arranged together with the obturator 6 near the print head 2, wherein the reservoirs 9 are formed as pressure equalization container. Between each of a reservoir 9 and a respective tank 3 for the ink, a return line 10 is formed in each case. This makes it possible to return the ink from the reservoir 9 back to the tank 3, and offers the advantage that in the case where an ink is not in use and thus the shutter 6 for this ink is closed, the ink between the ink Reservoir 9 and the tank 3 can be conveyed in a circuit and thus the deposition of components or components of the ink in the lines (feeder line 5, return line 10) is avoided.

The printhead 2 is formed in a manner known per se and consists of a distribution chamber 11, which is fed via the feed opening 8 in a first end region with ink and at a second end of ink, in this case eight, dispensing 12 emits. By operating the ejection devices 12, the ink is ejected through nozzles 13 disposed in a lower end portion of the print head 2 and thus applied to a print medium to be printed.

For conveying the inks or a cleaning agent from the tanks 3 and 4 into the print head, a pump 14 is arranged in the feeder lines 5. In order to prevent the ingress of impurities in the print head 2, a filter 15 are also arranged in each of the feeder lines 5. Analogously, in each case a pump 16 is formed in the return lines 10.

In the feeder lines 5 between each of the tanks 3 and the respective associated reservoir 9, a shut-off device 17 is arranged in each case. Accordingly, a shut-off device 18 is arranged in the return lines 10 between each of the tanks 3 and the reservoir 9 connected thereto. Through these shut-off elements 17, 18, the reservoirs 9 can be decoupled from the respective tanks 3 with respect to the pressure, so that a stabilization of the ink flow is achieved in the print head 2.

Since it may be necessary for the processing of inks of some ink systems to increase their temperature above room temperature, the tanks 3 are each equipped with heating elements 20 and thermometers 21. For the same reason, the print head 2 or the reservoirs 9 are also equipped with a heating element 22 and a thermometer 23.

Of course, it is also possible that the tanks 3 and the reservoirs 9 are each provided with a common heating element 20 and a common heating element 22. Accordingly, in most cases it will also be sufficient that the tanks 3 and the reservoirs 9 each have only one common thermometer 21 or a common thermometer 23.

For automated control of the entire inkjet printing device 1, this is equipped with a control device 24. Trained as a multi-way valve obturator 6 is controlled by the control device 24 so that always only one of the feeder lines 5 is continuously connected to the connection opening 7 and thus the feed opening 8 of the print head 2. From that tank 3, the supply line 5 is in the open state with respect to the connection opening 7, ink from this tank 3 is nachgefördert via the corresponding reservoir 9 in the distribution chamber 11 of the print head 2 by means of the pump 14. The control of the corresponding pump 14 is also carried out by the control device 24. The promotion of the ink from the reservoir 9 in the distribution chamber 11 can be effected both by the gravitational effect on the ink and by its own between the reservoir 9 and the obturator 6 arranged pump ( not shown).

To measure the level of the ink in the respective containers, the tanks 3, the reservoirs 9 and the distribution chamber 11 of the print head 2 are equipped in their interior with a level sensor 25. With these level sensors 25, the fill level can be continuously measured by the control device 24 connected thereto. In a preferred embodiment, these level sensors 25 are each arranged in an upper end region of the tanks 3, 4, the reservoirs 9 and the distribution chamber 11. In order to allow a pressure equalization with the ambient air pressure, the reservoirs 9 and the distribution chamber 11 of the print head 2 are each equipped with a ventilation opening 26. The vent 26 in turn has an air filter by which prevents dust particles from entering the nozzles 13 of the printhead 2 and clog them.

Alternatively, it is also possible that the print head 2 has no own ventilation opening 26 and no level sensor 25. In this embodiment, the distribution chamber 11 of the print head 2 is completely filled with ink and the pressure equalization with the ambient air pressure can take place via the vent opening 26 of the corresponding reservoir 9 or negative pressure can be applied to prevent leakage of the ink.

At the vent 26, a pressure control loop is preferably connected, by means of which the pressure in the distribution chamber 11 or the corresponding reservoir 9 can be adjusted so that leakage of ink from the nozzles 13 of the print head 3 is prevented.

The operation of the pump 14 and the obturator 6 by the control device 24 always takes place so that the level of the distribution chamber 11 and the reservoir 9 is in ink in a predetermined range.

The control device 24 is thus designed so that with its help, the distribution chamber 11 of the print head 2 and the reservoirs 9 can be filled with ink, this filling can be semi-automatic as well as fully automatic. With the help of the level sensors 25 in the tanks 3, 4, the control device 24 can also be used to refill the tanks 3, 4 from connected to this, set up separately from the ink jet printing Nachfüllbehältem with the corresponding inks or a cleaning medium. In this way, an uninterrupted operation of the inkjet printing device can be achieved.

The corresponding tank 3 as well as the reservoirs 9 and the print head 2 are held by the heating element 20 and the heating element 22 at the operating temperature required for the corresponding ink, the actual temperature being determined by the thermometers 21 and 23 in cooperation with the control device 24 and so the maintenance of the operating temperature can be monitored.

Now, if the ink jet printing device or the inkjet printer to be converted for printing on another medium, it will also be necessary in most cases that the inkjet printing device for processing on inks of another ink system, ie on inks of a different kind, is switched. With the inkjet printing device 1 according to the invention, according to Fig. 1 , This is advantageously possible because the printhead 2, ie the distribution chamber 11 and its Aussprühvorrichtungen 12 are cleaned with the nozzles 13 first with a cleaning medium. For this purpose, the shut-off device 6 designed as a multi-way valve is adjusted by the control device 24 such that the feed line 5 of the tank 4 is brought into the open position with respect to the connection opening 7. By controlling the pump 14 of the tank 4 cleaning agent is then pumped into the print head 2. By simultaneously pressing the Aussprühvorrichtungen 12 are Thus, the remainder of the remaining ink removed from the printhead 2 and the distribution chamber 11, the Aussprühvorrichtungen 12 and the nozzles 13 cleaned.

In addition to this cleaning process by supplying the cleaning medium, it is also possible that compressed air is blown into the print head 2 by a separate feeder line (not shown) and thus remaining in the print head 2 remains of the cleaning medium are removed from the print head 2. For this purpose, it is of course necessary that the vent opening 26 of the print head 2 by a corresponding valve (not shown) is closed. In particular, it is advantageous to form the ventilation openings 26 of the print head 2 and the reservoir 9 by means of a pressure regulating valve or a servo valve.

In an alternative embodiment, it is also possible, instead of using a cleaning medium, to blow out the "old" ink by applying overpressure to the ventilation openings 26.

For the process of ejecting residual ink or the cleaning medium, the ink jet printer is provided with a corresponding catching device, such as e.g. an ink absorption pad or a suitable receptacle.

Following this cleaning operation, the obturator 6 is set by the control device 24 so that now the feeder line 5 of that tank 3 is brought into the opened state with the ink of the new ink system, so that ink from the corresponding reservoir 9 into the distribution chamber 11 of the print head. 2 can flow. By actuating the corresponding pump 14, the ink is simultaneously conveyed from the corresponding tank 3 into the corresponding reservoir 9. As already described, the level of the distribution chamber 11 and the reservoir 9 is measured by means of the level sensors 25 and the control device 24 and thus kept within a predetermined range.

It should be particularly noted that the individual parts of the inkjet printing device 1 and the printhead 2 in the Fig. 1 are shown in an inaccurate and simplified manner. In particular, the volume of the tanks 3 and 4 in the concrete and practical embodiment of a corresponding ink jet printing device is a multiple of the volume of the distribution chamber 11 of the print head 2 and the reservoirs 9. It should also be noted that the feeder lines 5, the return lines 10 as well the signal lines or the Supply lines between the control device 24 and the obturator 6 or the level sensor 25, the heating elements 22 and the thermometers 23 are not rigid connections, but that they are designed as flexible lines or connections. Namely, during the printing process, the print head 2 and the reservoirs 9 are guided over the print medium to be printed, in some cases with very high speeds and accelerations, so that it is advantageous for the tanks 3 and 4, respectively, to also support the pumps 14 on one part of the print Ink jet printer are located opposite the printhead 2 at rest.

By a print head 2 as such, a color of an ink system can be processed. Is the same printhead 2 part of an ink jet printing device 1, according to Fig. 1 Thus, it is possible to switch between different ink systems, ie to change to the same color of another ink system. For a complete ink jet printing device, it is of course necessary for each additional color to be processed, a same arrangement of a print head 2 and the other components or elements, as shown in Fig. 1 are provided to provide. The tanks 3, the feeder lines 5, the reservoirs 9, the return lines 10, the shut-off devices 6, the pumps 14 and the filters 15 are designed for receiving inks of different ink systems as well as different colors. Furthermore, the tank 4 and the corresponding feeder line 5, the corresponding pump 14 and the corresponding filter 15 are designed for a cleaning medium in the form of a cleaning liquid, but these parts can also be designed for receiving compressed air as a cleaning medium.

The Fig. 2 shows a printhead 2 with two reservoirs 9 and a feed opening 27 for a cleaning medium. The print head 2 is connected via the feeder lines 5 with two tanks 3 for inks and a tank 4 for a cleaning medium.

At a first end region, the two reservoirs 9 of the print head 2 are connected by a feed opening 8 in each case to the connection opening 7 of a feeder line 5. At its second end region, the reservoirs 9 are connected by shut-off elements 6 to the distribution chamber 11 or an upper end region of the - in this embodiment eight - Aussprühvorrichtungen 12. The cleaning fluid supply port 27 is also connected to the upper end portion of the spray devices 12 by a shut-off device 6. At their first end regions, the reservoirs 9 also each have a ventilation opening 26 equipped with an air filter. The air filter prevents that dust particles penetrate into the print head 2 and cause a blockage in the nozzles 13.

As already in the figure description of Fig. 1 has been carried out, a pressure control loop is preferably connected to the ventilation opening 3, by which the pressure in the interior of the print head 2 can be adjusted so that an erroneous leakage of ink through the nozzles 13, ie without an actuation of the Aussprühvorrichtung 12, can be prevented.

In the feeder lines 5 of the tanks 3 for the inks and the tank 4 for the cleaning medium, a pump 14 and a filter 15 is arranged in each case. By means of the pumps 14, the inks or the cleaning medium can be conveyed into the print head 2. By the filter 15 can be prevented that impurities from the tanks 3 and 4 get into the print head 2. To control the inkjet printing device 1, this is equipped with the control device 24. The control of the various operating states of the ink jet printing device 1 can be both automated or program-controlled and semi-automatic, i. by manual setting of parameters on a control panel (not shown), the control device 24 or by manually setting the various operating conditions.

In order to control the supply of ink or of the cleaning medium, the control device 24 is connected to the pumps 14, to the shut-off devices 6 as well as to the fill level sensors 25. In order to maintain the inks at their required operating temperature during their processing, the tanks 3 and the printhead 2 are equipped with the heating elements 20 and 22 and the thermometers 21 and 23, respectively. To regulate the operating temperature of the inks, these heating elements 20 and 22 as well as the thermometers 21 and 23 are also in communication with the control device 24.

By opening one of the shut-off devices 6 of one of the two reservoirs 9, ink can flow from the reservoir 9 into the ejection devices 12, so that the supply of the ejection devices 12 with a corresponding ink of the corresponding ink system is guaranteed. The inflow of ink from the reservoir 9 in the region of the Aussprühvorrichtungen 12 is initially ensured by the fact that through the ventilation openings 26 can take place a pressure compensation. If a drop in the fill level in the reservoir 9 is registered by the fill level sensors 25 in cooperation with the control device 24, then the corresponding pump 14 is actuated by the control device 24, that from the corresponding tank 3, a sufficient amount of ink is nachgefördert in the reservoir 9.

In another embodiment of the printhead according to FIG. 2 It is also possible in an advantageous manner, the shut-off devices 6 form by a common multi-way valve.

The discharge of the ink through the nozzles 13 in the lower end of the Aussprühvorrichtungen 12 is carried out in a conventional manner by actuation of Aussprühvorrichtungen by corresponding data lines (not shown) or a corresponding control device (not shown) of the ink jet printer.

The Aussprühvorrichtungen 12 are equipped with an actuator 28 and a liquid diode 29. The actuator 28 may be formed as an electrorestrektives element which is disposed on an outer side of a resiliently deformable in the region of the Aussprühvorrichtung 12 housing wall of the nozzle head 2. If an electrical voltage is applied to the actuator 28 designed as an electrorestive element, a pressure pulse is thereby exerted on the ink located in the area of the ejection device, so that the ink moves on the one hand in the direction of the nozzle 13 and on the other hand in the direction of the liquid diode 29 becomes. By the liquid diode 29, however, the movement of the ink from the actuator 28 in the direction of the liquid diode 29 is largely suppressed, so that as a result of effect, a drop of the ink is ejected from the nozzle 13 to the printing medium to be printed. Alternatively, it is also possible to form the actuator 28 by a corresponding heating element, that heats the ink in the region of the Aussprühvorrichtung 12 so high that it leads to the formation of a bubble of vaporous ink, which finally to eject a drop of ink from the nozzle 13th leads. Of course, the actuator 28 can also be replaced by another physical effect, e.g. electrostatically, causing ejection of the ink.

Now, if the ink jet printing device to be switched to the processing of inks of another ink system, so the obturators 6 of the ink reservoir 9 are first closed and opened the feed opening 27 associated obturator 6 for the supply of a cleaning medium. By the control device 24, the pump 4 associated with the pump 14 is then controlled so that the cleaning medium is conveyed into the nozzle 2 and through the Aussprühvorrichtungen 12 and the nozzles 13. As a result, remaining in the region of Aussprühvorrichtungen 12 and the nozzles 13 ink residues removed from the nozzle 2 and cleaned these areas. In addition to cleaning with a cleaning medium in the form of a cleaning liquid, it is additionally possible for compressed air to be blown into the print head 2 by the pump 14, thus additionally liberating the ejection devices 12 and the nozzles 13 from the remaining residues of the cleaning liquid.

As already in the description of the figure Fig. 1 has been carried out, the ink jet printer for the described process of ejecting residual ink or the cleaning medium, a corresponding catching device, such as an ink absorbing pad or a suitable receptacle, is provided.

Following the described cleaning process, the corresponding shut-off device for the ink of the new ink system is now opened by the control device 24 so that it can flow into the spray devices 12 and the nozzles 13. Thus, the ink jet printing apparatus is set to process inks of the new ink system. For inkjet printing devices, which are designed to process more than one color for different ink systems, it is of course required that for each of the colors, a device be provided with the elements as in Fig. 2 shown, is formed. It is of course also possible that only a common control device 24 is provided.

As in the figure description of Fig. 1 has been carried out here is to emphasize that the individual parts are shown in an inaccurate and simplified. Thus, the volumes of the tanks 3 and 4 in the concrete and practical embodiment in a corresponding ink jet printing device, a multiple of the volume of the reservoirs 9 of the print head 2. Likewise, the feeder lines 5 and the various connections between the control device 24 and the shut-off valves 6, the pumps 14 and the heating elements 20 and 22 and the thermometers 21 and 23 and the level sensors 25 are flexible.

The Fig. 3 shows a detail of an ink jet printer with three ink jet printing devices 1, according to Fig. 2 in perspective and greatly simplified representation.

A printing medium 36 is moved in a direction 38 by a transport device 37 consisting of rollers. In a carriage 39 three printheads 2 are fixed, so that they are in a small distance above the printing medium 36 in the cross-feed direction, ie, in a direction 40 to the direction 38 of the movement of the pressure medium medium direction 40, can be moved. For movement of the carriage 39 in the transverse feed direction (direction 40), this is guided along two transverse guide tracks 41. During this movement of the printheads 2 above the print medium 36, the printing of the print medium 36 with the ink ejected from the printheads 2 is performed. The ink is to be conveyed from the respective tanks 3 through the pumps 14 and the feeder lines 5 in the printheads 2. The feeder lines 5 and the data and control lines (not shown) are guided, in a manner known per se, through a flexible conduit 42. In this case, the one end portion of the duct 42 is fixed to a fixed part of the frame (not shown) of the ink jet printer, while the second end portion of the duct 42 is fixed to the carriage 39.

To maintain the inks in the supply lines 5 at the required operating temperature, they are connected to a heating element (not shown) and a thermometer (not shown). Of course, it is also possible that - in particular over the course of the duct 42 away - the feeder lines 5 are connected to a common heating element and / or a common thermometer.

In modern inkjet printers high printing performance occur in the movement of the carriage 39 with the printheads 2 sometimes very high accelerations. The acceleration forces acting thereon on the ink in the print heads 2 can lead to undesired pressure fluctuations of the ink in the spray devices 12 or in the nozzles 13 (FIG. Fig. 1 . Fig. 2 ) to lead. As a result, there are variations in the volumes of the ink droplets ejected through the nozzles 13, or the suction of air or leakage of ink, and thus the deterioration of the image quality. To avoid corresponding pressure fluctuations contributes that, as already in the figure descriptions of Fig. 1 and 2 has been listed, the distribution chamber 11 and the reservoirs 9 are formed with ventilation openings 26 and 26 pressure control loops are connected to the ventilation openings. Through these ventilation openings 26, a pressure equalization with the ambient air pressure is possible. To avoid pressure differences between different Aussprühvorrichtungen 12 of a printhead 2 (this is a system of communicating vessels) also contributes that the Aussprühvorrichtungen 12 and the nozzles 13 are perpendicular to the direction 40, that is aligned perpendicular to the transverse feed direction of the carriage 39 , As a third measure to avoid pressure fluctuations is finally provided, that the feeder lines 5 and the return lines 10 and the lines between the obturator 6 and the print head 2 are formed from an elastically recoverable deformable material. In particular, the said lines are formed with a predeterminable force in the radial direction elastically recoverable deformable.

With the inkjet printing devices 1, according to Fig. 1 respectively. Fig. 2 , it is possible to make inkjet printers that allow easy conversion to process inks of different ink systems. Due to the formation of inkjet printers with inkjet printing devices 1 according to the invention, the corresponding inkjet printers can be used universally with very short changeover times. The other elements of such an inkjet printer are, on the one hand, a transport device for a print medium 36 to be printed and, on the other hand, a transport device or a drive for moving the print heads 2 over the print medium 36. A corresponding inkjet printer also has a control device which is connected to the drives for the transport device for the printing medium 36 and the transport device for nozzle heads 2 and the carriage 39 is connected and on the other hand via a system of data lines or via a data network, which can be controlled by the control device, the printheads 2 such that from the image information data on the corresponding image can be applied to the printing medium 36 to be printed. In inkjet printers with a plurality of printheads 2, it is of course also possible that a plurality of printheads 2 process the same color. For this, it is also possible that tanks 3 of a plurality of ink jet printing apparatuses 1 for inks of a same ink system and a same color are respectively formed by common tanks 3.

For the sake of order, it should finally be pointed out that in order to better understand the structure of the inkjet printing device or of the print head, this or its components have been shown partially unevenly and / or enlarged and / or reduced in size.

The task underlying the independent inventive solutions can be taken from the description.

Above all, the individual in the Fig. 1 ; 2 ; 3 shown embodiments form the subject of independent solutions according to the invention. The relevant objects and solutions according to the invention can be found in the detailed descriptions of these figures.

REFERENCE NUMBERS

1

Inkjet printing apparatus

2

printhead

3

tank

4

tank

5

feeder line

6

shutoff

7

port opening

8th

supply opening

9

reservoir

10

Return line

11

distribution chamber

12

Aussprühvorrichtung

13

jet

14

pump

15

filter

16

pump

17

shutoff

18

shutoff

19 20

heating element

21

thermometer

22

heating element

23

thermometer

24

control device

25

level sensor

26

vent

27

supply opening

28

actuator

29

fluid diode

36

print media

37

transport means

38

direction

39

carriage

40

direction

41

Transverse guideway

42

duct

Claims (38)

1. Inkjet printing device with at least one print head, whereby several tanks (3, 4) for inks and/or a cleaning medium are arranged in front of a connection opening (7) for the print head (2), and the tanks (3, 4) are connected to the connection opening (7) for the print head (2) by feed lines (5), and a stop element (6) is arranged between each tank (3, 4) and a distribution chamber (11) of the print head (2), wherein the tanks (3, 4) for the inks and/or the print head (2) are designed to have a heating element (20, 22) and/or a thermometer (21, 23).
2. Inkjet printing device according to claim 1, wherein a reservoir (9) is disposed in the feed line (5) between the stop element (6) and the tank (3, 4).
3. Inkjet printing device according to claim 1 or 2, wherein the reservoir (9) is designed as a pressure compensating container and/or for applying a negative pressure.
4. Inkjet printing device according to one of the preceding claims, wherein at least one reservoir (9) is disposed in the print head (2).
5. Inkjet printing device according to one of the preceding claims, wherein the stop element (6) is designed as a multiway valve.
6. Inkjet printing device according to one of the preceding claims, wherein a pump (14) is disposed between each tank (3, 4) and the connection opening (7).
7. Inkjet printing device according to one of the preceding claims, wherein a filter (15) is disposed between each tank (3, 4) and the connection opening (7).
8. Inkjet printing device according to one of the preceding claims, wherein a stop element (17) is disposed in the feed line (5) between each tank (3) and the reservoir (9) connected to it.
9. Inkjet printing device according to one of the preceding claims, wherein a stop element (18) is disposed in the return line (10) between each tank (3) and the reservoir (9) connected to it.
10. Inkjet printing device according to one of the preceding claims, wherein the reservoirs (9) are provided with a heating element (20, 22) and/or a thermometer (21, 23).
11. Inkjet printing device according to one of the preceding claims, wherein the tanks (3, 4) are provided with have a common heating element (20) and/or a common thermometer (21).
12. Inkjet printing device according to one of the preceding claims, wherein the feed lines (5) are connected to a heating element and/or a thermometer.
13. Inkjet printing device according to one of the preceding claims, wherein a common heating element and/or a common thermometer is allocated to several feed lines (5).
14. Inkjet printing device according to one of the preceding claims, wherein the print head (2) is provided with a heating element (22) and/or a thermometer (23).
15. Inkjet printing device according to one of the preceding claims, wherein the tanks (3, 4), the feed lines (5), the reservoirs (9), the stop elements (6), the pumps (14, 16) and the filters (15) are designed for holding inks of different ink systems and/or different colors.
16. Inkjet printing device according to one of the preceding claims, wherein the tanks (3, 4), the feed lines (5), the reservoirs (9), the stop elements (6), the pumps (14, 16) and the filters (15) are designed for holding a cleaning fluid and/or compressed air as a cleaning medium.
17. Inkjet printing device according to one of the preceding claims, wherein a filling height sensor (25) is disposed in an interior of the reservoir (9) and/or the tank (3, 4) and/or the distribution chamber (11) for the inks.
18. Inkjet printing device according to one of the preceding claims, wherein the filling height sensor (25) is disposed in a top end region of the reservoir (9) and/or the tanks (3, 4) and/or the distribution chamber (11).
19. Inkjet printing device according to one of the preceding claims, wherein the reservoir (9) for the inks is provided with at least one ventilation opening (26).
20. Inkjet printing device according to one of the preceding claims, wherein the distribution chamber (11) of the print head (2) is provided with at least one ventilation opening (26)
21. Inkjet printing device according to one of the preceding claims, wherein a pressure control valve, in particular a servo valve, is disposed in the ventilation opening (26).
22. Inkjet printing device according to one of the preceding claims, wherein a pressure control circuit is connected to the ventilation opening (26).
23. Inkjet printing device according to one of the preceding claims, wherein an air filter is disposed in the ventilation opening (26).
24. Inkjet printing device according to one of the preceding claims, wherein the feed line (5) is designed so that it is able to rebound elastically.
25. Inkjet printing device according to one of the preceding claims, wherein the feed line (5) is designed so that it is able to rebound elastically in the radial direction with a predefinable force.
26. Inkjet printing device according to one of the preceding claims, wherein the reservoir (9) is connected to the tank (3, 4) by a return line (10) and a pump (16).
27. Inkjet printing device according to one of the preceding claims, wherein tanks (3, 4) are connected to several print heads via independent stop elements (6).
28. Inkjet printing device according to one of the preceding claims, wherein the stop elements (6, 17, 18) and/or the pumps (14, 16) and/or the filling height sensors (25) and/or the heating elements (20, 22) and/or the thermometers (21, 23) are connected to a control device (24).
29. Inkjet printing device according to one of the preceding claims, wherein the control device (24) is designed for controlling the filling of the distribution chamber (11) and/or the reservoir (9) with ink.
30. Inkjet printing device according to one of the preceding claims, wherein the control device (24) is designed for filling tank (3) with ink and/or for filling tank (4) with cleaning medium.
31. Print head for inkjet printing devices according to one of claims 1 to 30, incorporating the distribution chamber (11) for releasing ink into one or more spray devices (12) and with a ventilation opening (26), wherein several reservoirs (9) for inks and/or a cleaning medium are disposed in the print head (2), each with a feed opening (8, 27) at a first end of the reservoir (9) and a stop element (6) between a second end of the reservoir (9) and the distribution chamber (11) of the spray device (12).
32. Print head according to claim 31, wherein the reservoir (9) for the inks is provided with at least one ventilation opening (26).
33. Print head according to claim 31 or 32, wherein a pressure control valve, in particular a servo valve, is disposed in the ventilation opening (26).
34. Print head according to one of claims 31 to 33, wherein a pressure control circuit is connected to the ventilation opening (26).
35. Print head according to one of claims 31 to 34, wherein an air filter is disposed in the ventilation opening (26).
36. Print head according to one of claims 31 to 35, wherein the print head (2) is provided with a heating element (22) and/or a thermometer (23).
37. Print head according to one of claims 31 to 36, wherein the reservoirs (9), the distribution chambers (11), the stop elements (6) and the spray device (12) are designed for holding inks of various ink systems and various colors.
38. Print head according to one of claims 31 to 37, wherein the reservoirs (9), the distribution chambers (11), the stop elements (6) and the spray device (12) are designed for holding a cleaning liquid and/or compressed air as a cleaning medium.

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